This proposal is a competitive renewal for Ohio State University's participation in the cooperative multicenter network of maternal-fetal medicine units. The purpose of the network is to investigate problems in clinical obstetrics, particularly those related to the prevention of low birth weight. We have described the academic productivity of the members of our research team during the past four years in the network and provided current information about our population and facilities. We are committed to working cooperatively with network staff and member units in identifying issues for research, developing and implementing protocols, collecting and transmitting quality data, and analyzing and publishing results of MFMU trials.